Automatic conversion of return values

mock.go

@@ -61,9 +61,10 @@ func mockMethod(m *mock.Mock, method reflect.Method) any {
 		inValues = inValues[1:] // skip receiver
 		in := make([]any, len(inValues))
 		for i, val := range inValues {
-			if val.IsZero() {
+			switch {
+			case val.IsZero():
 				in[i] = nil
-			} else {
+			default:
 				in[i] = val.Interface()
 			}
 		}
@@ -73,9 +74,12 @@ func mockMethod(m *mock.Mock, method reflect.Method) any {
 		}
 		outValues = make([]reflect.Value, len(out))
 		for i, val := range out {
-			if val == nil {
+			switch {
+			case val == nil:
 				outValues[i] = reflect.Zero(outTypes[i])
-			} else {
+			case reflect.TypeOf(val) != outTypes[i]:
+				outValues[i] = reflect.ValueOf(val).Convert(outTypes[i])
+			default:
 				outValues[i] = reflect.ValueOf(val)
 			}
 		}

mock_test.go

@@ -21,6 +21,7 @@ func TestMock(t *testing.T) {
 		ManyArgs(a, b, c int16, d, e, f int32, g, h, i int64, j, k, l uintptr, x float32) (r1, r2 int, r3, r4 float32)
 		UncommonArgs(UncommonType, *UncommonType) (UncommonType, *UncommonType, reflect.Type)
 		StackArg([32]int)
+		ConvertReturnValue() (int16, <-chan int)
 	}
 	i, m := Mock[TestInterface]()
 
@@ -103,6 +104,13 @@ func TestMock(t *testing.T) {
 		m.AssertCalled(t, "StackArg", arg)
 	})
 
+	t.Run("convert return value", func(t *testing.T) {
+		ch := make(chan int)
+		m.On("ConvertReturnValue").Return(1, ch)
+		_, _ = i.ConvertReturnValue()
+		m.AssertCalled(t, "ConvertReturnValue")
+	})
+
 	t.Run("multiple instances", func(t *testing.T) {
 		type Fooer interface {
 			Foo() int